ABS – Troubleshooting
35B-14
INSPECTION PROCEDURE 4
When the ignition key is turned to “START”, the ABS
warning lamp does not illuminate.
Probable cause
The ABS-ECU is powered through IG2 which is turned off when the ignition key
is in START position. The ABS warning lamp is powered through IG1 which is not
turned off even when the ignition key is in START position. So the cause must be
a defective circuit on valve relay side.
D Malfunction of wiring harness or connector
D Malfunction of valve relay
OK
Check the trouble symptom.
NG
Check the harness between the com-
bination meter and valve relay, and
repair if necessary.
OK
Check the motor for operation.
NG
Check the harness between the valve
relay and ground, and repair if neces-
sary.
OK
Check the following connector:
A-76
NG
Repair
OK
Measure at valve relay connector A-76.
D Disconnect the connector and
measure at the harness side.
D Disconnect ABS-ECU connector
B-25.
D Ignition switch: ON
D Voltage between 3 and body
ground
OK: Battery voltage
NG
Check the following connectors
and diode:
A-76, B-26
NG
Repair
ABS valve relay check.
NG
Replace the valve relay.
INSPECTION PROCEDURE 5
Brake operation is abnormal
Probable cause
The varies depending on the driving conditions and the road surface conditions, so
problem diagnosis is difficult. However, if a normal diagnosis code is displayed, carry
out the following inspection.
D Improper installation of wheel speed sensor
D Incorrect sensor harness contact
D Foreign material adhering to wheel speed sensor
D Malfunction of wheel speed sensor
D Malfunction of wheel bearing
D Malfunction of hydraulic unit
D Malfunction of ABS-ECU
NG
Repair
Hydraulic unit check
OK
Wheel speed sensor inspection. [Refer to Inspection Procedure
for “when either of diagnosis codes No. 11 to 14 is output” (P.35B-3).]
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